THURSDAY, Feb. 14 (HealthDay News) --Opening the windows at home may help pregnant women reduce their risk for preterm birth or low birth weight, a new study indicates.

Researchers suggested the increase in fresh air could help protect expectant mothers from exposure to secondhand smoke and other volatile organic compounds that can be found indoors.

For the study, published online and in the April issue of the American Journal of Public Health, researchers questioned more than 1,760 mothers in Los Angeles about the quality of air in their home while they were pregnant. They were asked about their exposure to secondhand smoke, how often they opened the windows and how often they used hairspray, insect spray and nail polish at home.

Although the researchers did not link the use of hairspray or other household products with preterm birth or low birth weight, they did find that opening the windows at home reduced the women's risk for these complications of pregnancy.

The study showed that women exposed to secondhand smoke at home who opened their windows for less than half the day were three times more likely to experience low birth weight and were 92 percent more likely to have a preterm birth.

Even if they were not exposed to secondhand smoke, women who didn't open their windows very often were 49 percent more likely to have a baby with low birth weight and 25 percent more likely to have a preterm delivery than women in homes with better ventilation.

"As there is no risk-free level of secondhand smoke, pregnant women should be advised to avoid secondhand smoke exposure whenever possible, or mitigate secondhand smoke exposure by limiting smoking by household members to outdoor spaces or ventilating their home," the authors wrote.

While the study found an association between opening windows and preterm birth, it did not establish a cause-and-effect link.